Sidewalk Fossils

Introduction:

Paleontology, the study of fossils, is a high interest subject at all
grade levels. The suggestions and lesson plans given here can be
adapted to the ability and grade level of any student k-12. While
these activities don't directly refer to dinosaurs, they will help
students to understand the processes by which paleontologists have
learned so much about the appearances and life styles of dinosaurs.
They also prepare students for a better understanding of fossils
seen in museums and at fossil sites.

Fossils are the remains of living things or their signs (foot prints,
etc.) preserved in rocks. Fossils are formed
when organisms (living things) or their marks are buried in mud,
sand or other sediments, which then become compacted and lithified
(turned into rock). When the rock formation is later uplifted
and eroded, the fossils are exposed.

Sidewalk fossils the remains or signs of organisms preserved in
synthetic rocks. (Synthetic is just as real as natural, but is
put together by humans.) When concrete is wet (like mud) leaves
twigs etc. may fall into it, and sometimes actually covered during the
finishing process. Others may just be pressed into the surface,
like footprints, or wheel tracks.

Teacher preparation:

Keep an eye open as you walk on areas paved with concrete on the school
grounds or in near by neighborhoods. Look for impressions of
leaves, seeds, or other plant parts. Also watch for tracks of
dogs, cats, humans, or other critters. And wheel tracks from
skates, skate boards, bicycles, etc. Take notes of location,
type, quantity and quality of the fossils. These notes will be
useful
in planning field trips, or directions to students.

Student preparation:

Initiate class discussion; "What do you think of when you hear
the word, fossil?"
Being a "What do you think" question, all responses
can be accepted without correction or criticism. Do not allow any
student to "put down" another's response. The ideas may be listed
on the board or overhead.

The word "dinosaur" will undoubtedly come up during the discussion,
which will help spark enthusiasm for the study.

Define; "Are all fossils dinosaurs? Of course not.
In fact, only a very small percentage of fossils are dinosaurs.
Though they are perhaps the most fascinating group of fossils."

"Let's summarize our discussion by writing a definition for the word
"fossil".
(It should have a meaning close
to, "A fossil is a part or trace of a living thing preserved
in rock." That includes bones,
leaves, logs, also
impressions, tracks, burrows, nests, etc.)
Having some real fossils to show would help at this time.

Preliminary explanation:

The relevant portion of a science book, or an appropriate video may
serve this purpose.

Fossils are formed when: Erosion removes small particles
of soil and rock from higher parts of the land, and deposits them in
lower places, frequently oceans or lakes. These deposits, known
as sediments are made of sand, dust, mud, etc. If dead plants or
animals are
deposited in the sediments and are buried by more sediment before they
completely decay, fossils may form. When the sediments become
lithified (turn into stone) the process of fossilization is complete.
Later, up lifting and erosion may bring the fossils back to the
surface where we find them.